Integrated circuit (IC) chips are usually mounted on IC packages. Different types of IC packages cater to different types of applications and requirements. With the increase in processing power, heat dissipation has become one of the core issues in IC packaging. The heat generated by the IC chip in a package affects the overall performance and reliability of the device. Heat dissipation is thus an important aspect in IC packaging because unwanted heat in a circuit needs to be dissipated to prevent an excessive rise in temperature that could possibly affect the performance of the circuit.
The thermal resistance of an IC package is one measure of the ability of the IC package to transfer heat generated by the IC chip out of the IC package. An IC package with a high thermal resistance has a low thermal performance because of its inefficiency in transferring heat generated by its IC chip. Therefore, packages that have a high thermal resistance are unsuitable for high power applications, e.g., circuitry that are operating above 3 watts.
The thermal resistance in an IC package depends very much on the materials used in that IC package. For example, in a conventional wire-bond ball grid array (BGA), the molding compound used may have a low thermal conductivity and would thus be a poor heat conductor. As such, a conventional wire-bond BGA package may only be suitable for low power applications. An embedded heat slug may be used to improve the thermal conductivity of an IC package. However, the use of a heat slug limits the size of the die as it takes up a substantial substrate area.
Therefore, it is desirable to reduce the thermal resistance of an IC package to improve its thermal performance. It is also desirable to have a cost-effective method to reduce the thermal resistance without limiting the size of the die that can be mounted on the IC package. It is within this context that the invention arises.